Phosphorus in relation to dominant cropping sequences in India: chemistry, fertility relations and management options.

Abstract

Soils vary widely in their capacities to supply phosphorus (P) to crops because only a small fraction of the total P in soil is available to crops. Thus, the crop growth and yield are likely to suffer adversely unless soil is endowed with adequate native supply of plantavailable P, or else the soil receives readily available (inorganic) P fertilizers. In order to rationalize fertilizer P application to support sustained high productivity on one hand and address the environmental and economic concerns on the other, an in-depth understanding of native P supplies and P dynamics in soil is inevitable. In this context, the present article takes stock of the available information on the occurrence of P in soils, chemistry of P in soil, P quantity, intensity, and buffer capacity attributes of different soils vis-àvis the P uptake modelling, P dynamics in soil, P management in important cropping systems for enhancing its use efficiency, soil testing for plant-available P to prescribe fertilizer P application and losses of P through erosion and runoff to the water bodies leading to eutrophication.